Vicky sure got icky-er as this show went on...

At first she was just a mean teenager who was babysitting because she was too lazy to go out and get a real job and wanted to be the one in control as opposed to being given orders to do. Though a bully she didn't really intend any actual bodily harm to befall Timmy or his friends because if anything extremely bad would happen she'd get fired and get in trouble, which is why she spent some of the episode "The Big Problem" trying to find Timmy after he grew up and assumed he went missing. As the show went on Vicky became more and more of a sociopath and has actually threatened to use lethal weaponry and intentionally try to scar, burn, and completely dispose of others which includes Timmy, her other clients, and even her family.

Vicky started out as kind of an amusing character but the joke that she's a mean babysitter obviously ran out of steam quick and now she's just plain disturbing. They shoulda retired this character years ago, actually they shoulda ended this whole years ago...